Magnesium alloy material for forming, magnesium alloy formed body, and manufacturing method of magnesium alloy formed body

ABSTRACT

A magnesium alloy material for forming which can yield a formed body with high formability without using a lubricating oil or a solid lubricant such as molybdenum disulfide, a magnesium alloy formed body which is obtained by forming the magnesium alloy material for forming, and a manufacturing method of the magnesium alloy formed body are provided. A magnesium alloy material for forming which exhibits a friction coefficient of 0.2 or below at a forming temperature of 350° C. or below is obtained by coating a surface of a magnesium alloy material with an organic resin such as a water-soluble urethane resin, a water-soluble polyester resin, a water-soluble acrylic resin or a water-soluble epoxy resin or a resin obtained by modifying any of these organic resins, or an organic resin formed of any of these resins which contains a silane coupling agent, a colloidal silica, a lubricant, a metal alkoxide or the like. Further, a magnesium alloy formed body such as an automobile part or a container is manufactured by forming a magnesium alloy material for forming.

TECHNICAL FIELD

The present invention particularly relates to a magnesium alloy materialfor forming which exhibits excellent formability, a magnesium alloyformed body which is obtained by forming the magnesium alloy materialfor forming, and a manufacturing method of the magnesium alloy formedbody.

BACKGROUND ART

Attempts have been made to use a light-weighted magnesium alloy as amaterial for manufacturing members of an exterior casing of miniaturizedportable electronic equipment such as mobile communication equipment ora notebook-type personal computer, a material for manufacturing membersof a large-sized casing such as a traveling suitcase or a documentaccommodating attaché case, a material for manufacturing automobileparts such as a hood, a trunk lid, doors or fenders and the like.However, magnesium alloy exhibits poor formability and hence, it isextremely difficult to perform forming with a high degree of forming. Asa method for forming such hard-to-form magnesium alloy by drawing, therehave been proposed several methods including a method which heatsmagnesium alloy to a recrystallization temperature region at the time offorming including a method which performs drawing after heating a die, apunch, and a wrinkle pressing member of a drawing device to anapproximately 150 to 400° C. (see patent document 1, for example), amagnesium-alloy-made hard-case manufacturing method which heats a die, apunch and a blank holder, and heats magnesium to a recrystallizationtemperature region by way of these forming tools, and forms a magnesiumblank into a box shape by hot deep drawing while inducing an annealingeffect in which magnesium is easily recrystallized, softened anddeformed by heating (see patent document 2, for example), a method whichmounts a sheet made of pure magnesium, pure aluminum, a resin or thelike which is softer than a sheet made of magnesium on at least onesurface of a punch and a die, and performs plastic forming (see patentdocument 3, for example), a method which mounts a fluororesin film onupper and lower surfaces of a heated magnesium thin plate as a heatinsulating material, and performs press forming at a high temperatureand the like (see patent document 4, for example). As indicated in theseproposals, in performing forming such as drawing to the magnesium alloy,it is inevitable to heat the magnesium alloy to a recrystallizationtemperature region.

Further, there has been also proposed a method which uses a lubricantfor facilitating forming. For example, there have been proposed a methodwhich forms a super-hard thin layer made of titanium nitride ordiamond-like carbon on a mold surface of a press mold by coating (seepatent document 5, for example), and a method which performs formingusing a plastic forming oil for magnesium alloy or aluminum alloycontaining biodegradable oil and fat, a rust-proofing lubricant, anextreme-pressure additive, an organic zinc compound, and an organicmolybdenum based compound (see patent document 6, for example). However,all of these methods are applicable to the cold forming and hence, inperforming the forming at a forming temperature which exceeds 200° C. asin the case of the above-mentioned examples, an effective lubricatingeffect cannot be acquired.

As prior art literatures relevant to the present invention, thefollowing are named.

Patent document 1: JP-A-2003-290843Patent document 2: JP-A-2002-254115Patent document 3: JP-A-2001-300643Patent document 4: JP-A-06-328155Patent document 5: JP-A-2003-154418Patent document 6: JP-A-2003-105364

DISCLOSURE OF THE INVENTION Task to be Solved by the Invention

It is an object of the present invention to provide a magnesium alloymaterial for forming which exhibits excellent lubricating effect withina temperature range of 350° C. or below, and can be formed into a formedbody with high formability without using lubricating oil or a solidlubricant such as molybdenum disulfide, a magnesium alloy formed bodywhich is obtained by forming the magnesium alloy material for forming bypressing, punch-stretching, drawing or the like, and a manufacturingmethod of the magnesium alloy formed body.

Means for Solving the Problems

To achieve the above-mentioned object, a magnesium alloy material forforming of the present invention is formed by covering a surface of amagnesium alloy material with an organic resin which is constituted ofone, two or more resins selected from a group consisting of awater-soluble urethane resin, a water-soluble polyester resin, awater-soluble acrylic resin, a water-soluble epoxy resin, and a resinproduced by modification of any one of the organic resins, wherein afriction coefficient of the magnesium alloy material at a formingtemperature of 350° C. or below is set to 0.2 or below (claim 1).

In the magnesium alloy material for forming (claim 1), the organic resincontains one, two or more agents selected from a group consisting of asilane coupling agent, colloidal silica, a lubricant and a metalalkoxide (claim 2).

In the magnesium alloy material for forming (claim 1 or 2), the organicresin contains a heat-resistance imparting agent (claim 3).

In the magnesium alloy material for forming (claim 3), theheat-resistance imparting agent is a siloxane compound (claim 4).

Further, the magnesium alloy formed body of the present invention is amagnesium alloy formed body which is obtained by forming the magnesiumalloy material for forming (claims 1 to 4) (claim 5).

In the magnesium alloy formed body (claim 5), the magnesium alloy formedbody is an automobile part (claim 6) or a container (claim 7).

In the magnesium alloy formed body (claim 7), the container is acontainer formed by drawing (claim 8).

In the magnesium alloy formed body (claim 7), a drawing ratio of thecontainer formed by drawing is 4.0 or below (claim 9).

Further, the manufacturing method of a magnesium alloy formed body ofthe present invention includes the steps of: preparing a magnesium alloymaterial for forming which is formed by covering a surface of amagnesium alloy material with an organic resin which is constituted ofone, two or more resins selected from a group consisting of awater-soluble urethane resin, a water-soluble polyester resin, awater-soluble acrylic resin, a water-soluble epoxy resin, and a resinproduced by modification of any one of the organic resins; and formingthe magnesium alloy material for forming within a temperature range of350° C. or below (claim 10).

In the manufacturing method of a magnesium alloy formed body (claim 10),as the organic resin, an organic resin containing one, two or moreagents selected from a group consisting of a silane coupling agent,colloidal silica, a lubricant and a metal alkoxide is used (claim 11).

In the manufacturing method of a magnesium alloy formed body (claim 11),as the organic resin, an organic resin further containing aheat-resistance imparting agent is used (claim 12).

In the manufacturing method of a magnesium alloy formed body (claim 12),as the heat-resistance imparting agent, a siloxane compound is used(claim 13).

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention is explained in detail.

As a magnesium alloy material used in the manufacture of the magnesiumalloy formed body of the present invention, it is preferable to use puremagnesium or a magnesium alloy containing 1.0 to 9.0% by weight ofaluminum, 0.5 to 6.0% by weight of zinc, 0.05 to 2.0% by weight ofmanganese and magnesium and unavoidable impurities as a balance, andhaving a mean grain size of 2 to 50 μm, more preferably 2 to 10 μm(hereinafter, for the sake of brevity, both of pure magnesium andmagnesium alloy being referred to as magnesium alloy). A sheet materialof magnesium alloy made by extruding, cutting or hot-rolling isapplicable to the following forming. In using magnesium alloy as thesheet material, a thickness of the sheet material may preferably be setto 0.05 to 3.0 mm. A magnesium alloy material for forming is produced bycovering a surface of the magnesium alloy material with an organicresin.

As the organic resin which covers the surface of the magnesium alloymaterial by coating, it is preferable to use a water-soluble or awater-dispersing resin. That is, a water-soluble urethane resin, awater-soluble polyester resin, a water-soluble acrylic resin, and awater-soluble epoxy resin may preferably be used. A water-solubleacrylic modified polyester resin and a water-soluble phenyl siliconmodified acrylic resin which are formed by modifying the above-mentionedresins may also preferably be used. These organic resins may be used ina single form or in mixture consisting of two or more kinds of resins.An addition quantity of the organic resin may preferably be set to avalue which falls within a range from 20 to 85% by weight. When theaddition quantity of the organic resin is less than 20% by weight, aformed organic resin film is liable to be damaged by forming and hence,the addition quantity of less than 20% by weight is not desirable. Whenthe addition quantity of organic resin exceeds 85% by weight, althoughthere arises no problem with respect to properties thereof, the additionquantity exceeding 85% is not economical. Further, a temperatureexceeding 150° C. is often used preferably as a forming temperature ofmagnesium alloy material and hence, it is preferable to use an organicresin possessing the excellent heat resistance.

Although the organic resin film may be formed by applying the organicresin by coating to the above-mentioned magnesium alloy material in asingle form and by drying the applied resin, to enhance the formabilityand the corrosion resistance, the organic resin may contain thefollowing materials. With the addition of a silane coupling agent, theadhesiveness of the organic resin film to the magnesium alloy material,more particularly, the adhesiveness of the organic resin film to themagnesium alloy material at the time of forming can be remarkablyenhanced. The silane coupling agent is classified, based on kinds offunctional groups, into a vinyl-based silane coupling agent, anepoxy-based silane coupling agent, a styryl-based silane coupling agent,a methacryloxy-based silane coupling agent, an acryloxy-based silanecoupling agent, an amino-based silane coupling agent, an ureide-basedsilane coupling agent, a chloropropyl-based silane coupling agent, amercapto-based silane coupling agent, an isocyanate-based silanecoupling agent and the like. These coupling agents can be effectivelyused in the manufacturing method of a magnesium alloy formed body of thepresent invention. This is because these silane coupling agents exhibitthe excellent bonding property, that is, the excellent adhesiveness withrespect to almost all resins. To be more specific, the epoxy-basedsilane coupling agent KBM403 exhibits excellent bonding with theurethane-based resin, the epoxy-based resin or the like, and theamino-based silane coupling agent KBM903 exhibits excellent bonding withthe acrylic resin or the like and hence, these silane coupling agentsexhibit excellent adhesiveness with these resins. Further, various kindsof urethane-based resins are present besides the epoxy-based silanecoupling agent KBM403 and hence, the amino-based silane coupling agentKBM903 also can acquire an excellent effects. The organic resin film maypreferably contain not more than 5% by weight of silane coupling agent,and may more preferably contain not more than 1% by weight of silanecoupling agent. Even when an addition quantity of the silane couplingagent exceeds 5% by weight, the enhancement of adhesiveness is saturatedand hence, such excessive addition of the silane coupling agent becomeseconomically disadvantageous.

Further, the organic resin film increases hardness by containingcolloidal silica therein thus enhancing abrasion resistance and alsocorrosion resistance. The organic resin film may preferably contain notmore than 50% by weight of colloidal silica. When an addition quantityof colloidal silica exceeds 50% by weight, the organic resin filmbecomes excessively hard and hence, the formability of the organic resinfilm is deteriorated whereby cracks are liable to easily occur in theorganic resin film at the time of forming.

Further, with the addition of the lubricant in the organic resin,formability of the magnesium alloy material for forming formed byapplying the organic resin film to the magnesium alloy material isenhanced. As the lubricant, a higher fatty acid such as a lauric acid, amyristic acid, a palmitic acid or a stearic acid, a calcium salt, analuminum salt, a zinc salt, a barium salt or a magnesium salt of thesehigher fatty acid, ester of a higher fatty acid such as a lauric acid, amyristic acid, a palmitic acid or a stearic acid, polyolefine wax suchas polyethylene wax or polypropylene wax, fluorine-based wax such aspolytetrafluoroethylene, polychlorotrifluoroethylene, poly fluorinevinylidene or poly fluorine vinyl, mineral powder such as graphite,molybdenum disulfide or boron nitride can be used. The organic resinfilm may preferably contain not more than 20% by weight of lubricant.When an addition quantity of the lubricant exceeds 20% by weight, theadhesiveness of the organic resin film to the magnesium alloy materialat the time of forming is deteriorated.

Further, with the addition of metal alkoxide in the organic resin, theheat resistance of the magnesium alloy material for forming formed byapplying the organic resin film to the magnesium alloy material can beenhanced. As metal alkoxide, alkoxide of boron, aluminum, titanium,vanadium, manganese, iron, cobalt, copper, yttrium, zirconium, niobium,lantern, cerium, tantalum or tungsten can be named. Among these metalalkoxides, titanium-based alkoxide can preferably be used. The organicresin film may preferably contain not more than 10% by weight of metalalkoxide therein. When an addition quantity of metal alkoxide exceeds10% by weight, formability of the magnesium alloy material for formingformed by applying the organic resin film to the magnesium alloymaterial is lowered. Although the organic resin film may contain onekind of agent selected from the above-mentioned group consisting ofsilane coupling agent, the colloidal silica, the lubricant and the metalalkoxide in a single form, the organic resin film may contain two ormore kinds of these materials.

By applying the organic resin acquired by the above-mentioned manner tothe surface of the magnesium alloy material and by drying the organicresin, the organic resin film is formed. A thickness of the organicresin film may preferably be 0.1 to 50 μm, and more preferably be 1 to10 μm with respect to the thickness after drying. Although the magnesiumalloy material for forming is acquired in this manner, a frictioncoefficient of a surface of the magnesium alloy material for forming ata forming temperature may preferably be set to 0.2 or below. Thefriction coefficient at a forming temperature is a value of a frictioncoefficient at a temperature at which the magnesium alloy material forforming is formed and is measured using a contact-type frictioncoefficient measuring device made by SHINTO Scientific Co., ltd.(HEIDON) (Dynamic Strain Amplifier 3K-34D, Peeling/Slipping/ScratchingTESTER HEIDON-14).

The magnesium alloy material for forming obtained by the above-mentionedsteps exhibits the friction coefficient at a forming temperature of 0.2or below and hence, the magnesium alloy material for forming exhibitsexcellent formability. Accordingly, the magnesium alloy material forforming can be preferably formed without using lubricating oil or asolid lubricant such as molybdenum disulfide which have been usuallyused in applications such as drawing, forging, rolling and pressforging. Further, the magnesium alloy material for forming can be alsopreferably formed using the lubricating oil or the solid lubricant suchas molybdenum disulfide which have been usually used in combination withthe organic resin film and hence, the magnesium alloy material forforming can be continuously formed in conventional manufacturing stepswhich include an oil coating step by using the conventionalmanufacturing method of magnesium alloy material which requires coatingof lubricating oil and the manufacturing method of the present inventionwhich requires no oil coating in combination. Further, by drawing themagnesium alloy material for forming by heating the magnesium alloymaterial for forming within a temperature range not more than 350° C.,more preferably within a hot forming temperature range from 200 to 350°C., the formability is further enhanced compared to the formingperformed within a temperature range of less than 200° C. and hence, themagnesium alloy material for forming can be formed at high formability.However, when the forming is performed within the temperature rangeexceeding 200° C., the organic resin film is discolored by decomposion,or cracks occur in the organic resin film thus deteriorating appearanceand, at the same time, making the enhancement of formability difficult.Accordingly, in addition to the enhancement of heat resistance using theorganic resin alone, by allowing the organic resin film to furthercontain a heat resistance imparting agent, it is possible to performforming of the magnesium alloy material for forming in a stable mannerwithout discoloring the organic resin film or generating cracks in theorganic resin film within a hot forming temperature range of hightemperature from 200 to 350° C. whereby the formability can be alsoenhanced. As a result, in the forming of the magnesium alloy materialfor forming, the forming temperature which enables the acquisition offormability equal to the formability obtained by the conventionallyexercised forming which uses the lubricating oil can be further loweredwithin the temperature range of not more than 350° C. and hence, it ispossible to acquire an advantageous effect that the excessive heattreatment becomes unnecessary. It is needless to say that coating of thelubricating oil at the time of forming becomes unnecessary.

As the heat-resistance imparting agent, a heat-resistant resin such aspolyimide or siloxane compound may preferably be used. As a siloxanecompound, a polymer or a monomer of organosiloxane such asdimethylsiloxane, diethyl siloxane, methylethyl siloxane, diphenylsiloxane, methylphenyl siloxane, or polymer or monomer of organosiloxanemolecules which contains at least one substituent group or two or moresubstituent groups consisting of one kind, two or more kinds ofpolyalkylene oxide group, hydroxyl group, amide group, carboxyl group,sulfone group and amino group may preferably be used. The organic resinfilm may preferably contain 5 to 80% by weight of heat-resistanceimparting agents, and more preferably 10 to 60% by weight ofheat-resistance imparting agent. By adding the heat-resistance impartingagent to the organic resin film in this manner, it is possible toperform forming with high formability by heating the magnesium alloysheet for forming up to the hot forming temperature range from 200 to350° C. Here, although the organic resin may contain the heat-resistanceimparting agent in a single form, the organic resin may contain theheat-resistance imparting agent in combination with one kind or twokinds or more of the above-mentioned silane coupling agent, thecolloidal silica and the lubricant.

With respect to the magnesium alloy formed body which is obtained inthis manner, coating may be applied to the organic resin film whennecessary. Alternatively, the magnesium alloy formed body may bemanufactured by forming a coated material which is produced bypreliminarily applying coating on an organic resin film of theabove-mentioned magnesium alloy material for forming. It is needless tosay that the magnesium alloy material for forming can be used in a statewhere the magnesium alloy material is covered with only the organicresin film in a single form. Further, after forming magnesium alloyformed body using the magnesium alloy material for forming, the organicresin film may be dissolved and removed using an alkaline solution, orthe organic resin film may be removed by a shot blast method which blowsabrasive particles on a surface of the organic resin film and,thereafter, a surface treatment such as a known anodizing treatment orplating may be applied to the magnesium alloy formed body, or coatingmay be further applied to the magnesium alloy formed body to which thesurface treatment is applied.

Embodiment

Hereinafter, the present invention is explained in detail in conjunctionwith embodiments.

(Preparation of Magnesium Alloy Material for Forming)

As the magnesium alloy material for forming, magnesium alloy materialfor formings for testing which are given sample numbers 1 to 13 areprepared in the following manner. That is, to both surfaces of amagnesium alloy sheet containing following alloy contents and having asheet thickness of 0.4 mm, a resin solution shown in Table 1 or a resinsolution which is prepared by adding a silane coupling agent, colloidalsilica, a lubricant, a metal alkoxide or a heat resistance-impartingagent shown in Table 1 to the resin shown in Table 1 is applied using abar coater and is dried such that respective additives exhibit contentsshown in Table 1 in a post-drying state and a thickness of the resinfilm after drying assumes a value shown in Table 1.

<Alloy Contents>

Al: 3.1% by weight, Zn: 1.1% by weight, Mn: 0.31% by weight, balance: Mgand unavoidable impurity elements

<Average Grain Size>

8 μm

TABLE 1 heat water-soluble resistance- resin silane coupling colloidalmetal imparting content agent silica lubricant alkoxide agent filmsample (weight content content content content content thickness numberkind %) kind (weight %) (weight %) kind (weight %) kind (weight %) kind(weight %) (μm) 1 URE 80.0 — — 10 PTFE 10 — — — — 43 2 URE 59.5 KMB9030.5 35 PTFE  5 — — — — 2 3 URE 40.0 KMB903 1.0 50 — — — — DMSX  9 6 4AC-PES 34.5 KMB403 0.5 15 PTFE 15 — — DMSX 35 8 5 PES 68.0 KMB903 2.0 15PTFE 15 — — — — 3 6 PES 80.5 KMB403 4.5 — PTFE 15 — — — — 6 7 ACR 61.0KMB903 1.0 15 PTFE 20 TIET 3.0 — — 0.4 8 ACR 34.5 KMB903 0.5 25 — — — —MPSX 40 5 9 ACR 47.0 — — 48 — — — — MPSX  5 10 10 EF-ACR 64.5 KMB403 0.520 PTFE 10 TIET 5.0 — — 1.5 11 EPO 21.0 KMB403 1.0 — — — — — DMSX 78 3512 EPO 40.0 — — 25 PTFE 10 — — DMSX 25 5 13 URE + 80.0 — —  5 PTFE  5 —— MPSX 10 5 EPO 14 — — — — — — — — — — — — 15 — — — — — — — — — — — Fresin 50 μm Note) URE: urethane, PES: polyester, ACR: acryclic, EPO:epoxy, AC-PES: acryl-modified epoxy, EF-ACR: phenyl silicon modifiedacrylic, KMB903: amino-based silane coupling agent made by Shin-Etsuchemical Co., Ltd., KMB403: epoxy-based silane coupling agent made byShin-Etsu Chemical Co., Ltd., TIET: titanium ethoxide, PTFE:polytetrafluoroethylene, DMSX: dimethylsiloxane, MPSX:methylphenylsiloxane, F resin: applying fluororesin film having athickness of 50 μm to upper and lower surfaces of magnesium alloy sheetat the time of drawing

(Preparation of Magnesium Alloy Formed Body)

The magnesium alloy sheets for forming for testing which are obtained bythe above-mentioned manner and are given sample numbers 1 to 13 areformed into a container by drawing under following conditions. Withrespect to the forming temperatures, a dice and a blank holder have thesame temperature and only the temperature of a punch is set to a roomtemperature. Limiting drawing ratios of the formed bodies at the time ofdrawing are obtained and formability of these formed bodies isevaluated. Further, a friction coefficient at a forming temperature ismeasured using a friction coefficient measuring device made by SHINTOScientific Co., ltd. (HEIDON) to which a holder heater is attached. Inmeasuring the friction coefficient, the magnesium alloy material forforming fixed to the holder is heated at a forming temperature and,thereafter, the friction coefficient is measured under conditions wherea stainless steel ball having a diameter of 10 mm attached to the deviceis used as a contact ball, a measuring weight is set to 200 g, and ameasuring time is set to 1.6 mm/sec.

<Radius of Curvature R of Punch Shoulder>

5 mm

<Punch Temperature> 25° C. <Dice Temperature> 150° C., 200° C., 250° C.,300° C., 350° C. <Blank Holder Temperature> 150° C., 200° C., 250° C.,300° C., 350° C. <Drawing Speed>

1 mm/sec

<Lubricating Oil and Lubricant>

Neither Lubricating oil nor lubricant is used at the time of forming themagnesium alloy material of the present invention.

As comparison examples, magnesium alloy formed bodies are prepared inthe following manner. That is, the magnesium alloy formed body having asample number 14 is prepared as the comparison example by applyingcommercially available lubricating oil G3080 (made by NIHON KOHSAKUYUCO., LTD.) to both surfaces of the above-mentioned magnesium alloymaterial, and the magnesium alloy formed body having a sample number 15is prepared as the comparison example by mounting a fluororesin filmhaving a thickness of 50 μm on both surfaces of the magnesium alloymaterial. Then, drawing is applied to these comparison examples havingthe sample numbers 14, 15 under the substantially same conditions thuspreparing the magnesium alloy formed bodies for comparison. Here, withrespect to the magnesium alloy material having the sample number 14 onwhich a fluororesin film is not mounted, formability when a formingtemperature is low is extremely deteriorated thus making drawing of themagnesium alloy difficult. Accordingly, drawing is performed only when adice temperature and a blank holder temperature are 200° C. or above.Further, with respect to the magnesium alloy material having the samplenumber 15 which mounts a fluororesin film thereon, when a dicetemperature and a blank holder temperature are 350° C., the fluororesinfilm is heavily damaged thus making drawing of the magnesium alloymaterial difficult. Accordingly, drawing is applied to the magnesiumalloy material only when the dice temperature and the blank holdertemperature fall within a range from 150° C. to 300° C.

(Evaluation of Appearance of Organic Resin Film)

Appearances of organic resin films formed on surfaces of the magnesiumalloy formed bodies (containers formed by drawing) after forming areobserved with naked eyes and are evaluated based on the followingcriteria.

Excellent: Neither discoloring nor damages of the film are recognized.Good: Although slight discoloring of film is recognized, damages of thefilm which cause a serious problem in practical use are not recognized.Fair: Although discoloring and damages of film are recognized, themagnesium alloy material can be formed into a shape of the formed body(container formed by drawing), and can be directly used as an interiormember. Further, by applying a simple treatment removing abrasion or thelike to the film, aesthetic appearance can be obtained and hence, themagnesium alloy formed body can be sufficiently used as an exteriormember.Bad: Heavy damages on the film are recognized and, at the same time,abrasions which cause a serious problem in practical use are formed onthe surface of the formed body (container formed by drawing).

Results of these evaluations are shown in Tables 2 to 4.

TABLE 2 sample temperature at the time of measuring use of tool frictionlubricating limiting appearance sample temperature (° C.) coefficientfriction oil or drawing of organic number punch dice blank holder (° C.)coefficient lubricant ratio resin film distinction 1-1 25 150 150 1500.19 not used 1.9 excellent present invention 1-2 25 200 200 200 0.16not used 2.6 good present invention 1-3 25 250 250 250 0.12 not used 3.2good present invention 1-4 25 300 300 300 0.09 not used 2.8 fair presentinvention 2-1 25 150 150 150 0.20 not used 1.8 excellent presentinvention 2-2 25 200 200 200 0.17 not used 2.4 good present invention2-3 25 250 250 250 0.14 not used 2.9 good present invention 2-4 25 300300 300 0.11 not used 2.6 fair present invention 3-1 25 150 150 150 0.18not used 2.0 excellent present invention 3-2 25 200 200 200 0.16 notused 3.0 excellent present invention 3-3 25 250 250 250 0.13 not used3.8 excellent present invention 3-4 25 300 300 300 0.10 not used 3.8excellent present invention 3-5 25 350 350 350 0.09 not used 3.6 goodpresent invention 4-1 25 150 150 150 0.17 not used 2.2 excellent presentinvention 4-2 25 200 200 200 0.15 not used 3.2 excellent presentinvention 4-3 25 250 250 250 0.13 not used 4.0 excellent presentinvention 4-4 25 300 300 300 0.11 not used 4.0 excellent presentinvention 4-5 25 350 350 350 0.09 not used 3.8 good present invention

TABLE 3 sample temperature at the time tool of temperature measuring useof (° C.) friction lubricating limiting appearance sample blankcoefficient friction oil or drawing of organic number punch dice holder(° C.) coefficient lubricant ratio resin film distinction 5-1 25 200 200200 0.15 not used 3.3 excellent present invention 5-2 25 250 250 2500.14 not used 3.5 good present invention 5-3 25 300 300 300 0.11 notused 3.3 fair present invention 6-1 25 150 150 150 0.19 not used 2.4excellent present invention 6-2 25 200 200 200 0.17 not used 3.2 goodpresent invention 6-3 25 300 300 300 0.11 not used 3.0 fair presentinvention 7-1 25 150 150 150 0.17 not used 2.2 excellent presentinvention 7-2 25 200 200 200 0.14 not used 2.6 good present invention7-3 25 300 300 300 0.10 not used 2.3 fair present invention 8-1 25 200200 200 0.17 not used 2.8 excellent present invention 8-2 25 250 250 2500.15 not used 3.5 excellent present invention 8-3 25 350 350 350 0.11not used 3.2 good present invention 9-1 25 200 200 200 0.13 not used 2.8excellent present invention 9-2 25 250 250 250 0.12 not used 3.5excellent present invention 9-3 25 300 300 300 0.11 not used 3.5excellent present invention 10-1  25 150 150 150 0.16 not used 2.0excellent present invention 10-2  25 200 200 200 0.15 not used 2.8 goodpresent invention 10-3  25 300 300 300 0.11 not used 2.3 fair presentinvention 11-1  25 200 200 200 0.15 not used 2.6 excellent presentinvention 11-2  25 250 250 250 0.14 not used 3.1 excellent presentinvention 11-3  25 300 300 300 0.13 not used 3.1 excellent presentinvention 12-1  25 200 200 200 0.14 not used 2.5 excellent presentinvention 12-2  25 250 250 250 0.12 not used 3.0 excellent presentinvention 12-3  25 300 300 300 0.10 not used 3.0 excellent presentinvention

TABLE 4 sample temperature tool at the time temperature of measuring useof (° C.) friction lubricating oil limiting appearance sample blankcoefficient friction or drawing of organic number punch dice holder (°C.) coefficient lubricant ratio resin film distinction 13-1 25 200 200200 0.14 not used 2.4 excellent present invention 13-2 25 250 250 2500.12 not used 3.0 excellent present invention 13-3 25 300 300 300 0.10not used 2.9 good present invention 14-1 25 200 200 200 0.28 lubricatingoil 1.5 — comparison example 14-2 25 250 250 250 0.28 lubricating oil1.8 — comparison example 14-3 25 300 300 300 0.30 lubricating oil 1.8 —comparison example 15-1 25 150 150 150 0.20 F resin 50 μm 1.4 —comparison example 15-2 25 200 200 200 0.20 F resin 50 μm 2.7 —comparison example 15-3 25 250 250 250 0.20 F resin 50 μm 3.4 —comparison example 15-4 25 300 300 300 0.18 F resin 50 μm 3.0 —comparison example Note) —: not evaluated F resin: fluororesin filmhaving film thickness of 50 μm being mounted on upper and lower surfacesof magnesium alloy sheet at the time of drawing

As shown in Tables 2 to 4, the magnesium alloy material for forming ofthe present invention which is formed by covering the magnesium alloysheet with the organic resin exhibits excellent formability. That is,compared to the comparison example (sample number 14) which is formed bya conventional method in which lubricating oil is applied to themagnesium alloy sheet and drawing is applied to the magnesium alloysheet thereafter, the magnesium alloy material for forming of thepresent invention exhibits extremely excellent formability. Further,compared to the comparison example (sample number 15) which uses anexpensive fluororesin film as a lubricant and has been mainly used inresearch and development because of the most excellent formability inthe past, the magnesium alloy material for forming according to thepresent invention exhibits the equivalent or more formability.Accordingly, as a method which replaces a method using a fluororesinfilm which has a drawback in cost and productivity in mass production,the superiority of the magnesium alloy material for forming according tothe present invention is apparent. Further, when the organic resincontains the heat-resistance imparting agent, drawing can be applied tothe magnesium alloy material for forming at a high temperature up to350° C. When drawing is applied to the magnesium alloy material forforming at such a high temperature, the magnesium alloy material forforming can be formed into the magnesium alloy formed body (containerformed by drawing) by drawing with high degree of formability, wherein alimiting drawing ratio may take 4.0 as a maximum value.

INDUSTRIAL APPLICABILITY

The magnesium alloy sheet for forming of the present invention which isformed by covering the surface of the magnesium alloy material with theorganic resin which possesses lubricating property can be formed intothe magnesium alloy formed body with high formability. Particularly,when the organic resin contains the heat-resistance imparting agent suchas a siloxane compound, the magnesium alloy sheet of the presentinvention exhibits the excellent lubricating effect within a hot formingtemperature range from 200 to 350° C. Accordingly, the magnesium alloysheet for forming of the present invention can be used as a material formanufacturing the magnesium alloy formed bodies which include automobileparts such as a hood, a trunk lid, doors or fenders, a miniaturizedexterior casing of portable electronic equipment such as a mobilecommunication equipment or a notebook-type personal computer, and alarge-sized casing such as a traveling suitcase or a documentaccommodating attach case. The magnesium alloy sheet for forming of thepresent invention can be particularly used for manufacturing a containerformed by drawing with high formability in which a drawing ratio is 4.0or below.

1. A magnesium alloy material for forming, the magnesium alloy materialbeing formed by covering a surface of a magnesium alloy material with anorganic resin which is constituted of one, two or more resins selectedfrom a group consisting of a water-soluble urethane resin, awater-soluble polyester resin, a water-soluble acrylic resin, awater-soluble epoxy resin, and a resin produced by modification of anyone of the organic resins, wherein a friction coefficient of themagnesium alloy material at a forming temperature of 350° C. or below isset to 0.2 or below.
 2. A magnesium alloy material for forming accordingto claim 1, wherein the organic resin contains one, two or more agentsselected from a group consisting of a silane coupling agent, colloidalsilica, a lubricant and a metal alkoxide.
 3. A magnesium alloy materialfor forming according to claim 1, wherein the organic resin contains aheat-resistance imparting agent.
 4. A magnesium alloy material forforming according to claim 3, wherein the heat-resistance impartingagent is a siloxane compound.
 5. A magnesium alloy formed body which isobtained by forming the magnesium alloy material for forming accordingto claim
 1. 6. A magnesium alloy formed body according to claim 5,wherein the magnesium alloy formed body is an automobile part.
 7. Amagnesium alloy formed body according to claim 5, wherein the magnesiumalloy formed body is a container.
 8. A magnesium alloy formed bodyaccording to claim 7, wherein the container is a container formed bydrawing.
 9. A magnesium alloy formed body according to claim 8, whereina drawing ratio of the container formed by drawing is 4.0 or below. 10.A manufacturing method of a magnesium alloy formed body comprising thesteps of: preparing a magnesium alloy material for forming which isformed by covering a surface of a magnesium alloy material with anorganic resin which is constituted of one, two or more resins selectedfrom a group consisting of a water-soluble urethane resin, awater-soluble polyester resin, a water-soluble acrylic resin, awater-soluble epoxy resin, and a resin produced by modification of anyone of the organic resins; and forming the magnesium alloy material forforming within a temperature range of 350° C. or below.
 11. Amanufacturing method of a magnesium alloy formed body according to claim10, wherein as the organic resin, an organic resin containing one, twoor more agents selected from a group consisting of a silane couplingagent, colloidal silica, a lubricant and a metal alkoxide is used.
 12. Amanufacturing method of a magnesium alloy formed body according to claim11, wherein as the organic resin, an organic resin further containing aheat-resistance imparting agent is used.
 13. A manufacturing method of amagnesium alloy formed body according to claim 12, wherein as theheat-resistance imparting agent, a siloxane compound is used.